1. Field of the Invention
The present invention pertains to a device for measuring a figure, such as, for example, a linear planimeter or a polar planimeter. More particularly, the present invention is directed to a device for increasing a measurable range of a device that measures coordinates of a figure, a length of a line making up part of or extending along the figure, and similar dimensions or parameters of the figure.
2. Background and Material Information
A planimeter is a device having a tracing element or member provided at a free end of a measuring lever for tracing a figure before entering measured values into a computer in order to measure an area, a length, or coordinates of the figure. Examples of planimeters are disclosed, for example, in U.S. Pat. Nos. 4,616,419 and 5,515,299, the disclosures of which are incorporated herein in their entirety.
A measurable range of a typical measuring lever of the planimeter, obtained by turning the measuring lever, is determined by a physical length of the measuring lever of the planimeter. A measuring range of a planimeter by turning (rotating) the measuring lever is approximately 190 mm (approximately 56 degrees), from a center line in the case of a linear planimeter, or rotational range of a rotation arm pivoted on a fixed part and the measuring lever pivoted at the end of the rotation arm in the case of polar planimeter. It is inconvenient to reset the planimeter when the measuring lever is beyond the measurable range in order to measure the figure.
The inventor of the present application proposed a solution to these problems in Japanese Patent Application Number HEI 7-167606, which was filed on Jul. 3, 1995 (corresponding to U.S. patent application Ser. No. 08/671,257, filed on Jun. 26, 1996, now U.S. Pat. No. 5,727,329), the contents of which are expressly incorporated herein by reference in its entirety. According to this proposed solution, an auxiliary tracer arm is provided at the end of a measuring lever in order to increase the tracing range of the planimeter. However, while the auxiliary tracer arm reduces the severity of the problem, it does not totally eliminate the above-noted problems.